Drilling fluid

ABSTRACT

An aqueous drilling fluid dispersant and a method of drilling wells using as the drilling fluid dispersant 4allyldihydroxybenzene.

United States Patent Kablaoui et al. Feb. 15, 1972 [54] DRILLING FLUID 2,333,133 11/1913 Wayne ..252/8.5 2,681,371 6/1954 Gaydasch et al .....260/625 X lnvemorsi Mahmoud F Jack K918i", 2,894,993 7/1959 Schmerling ..260/62s x both of pp g Falls, 3,256,336 6/1966 Lange .....260/488 Assigneez Texaco Inc, New YorkI N-Y- Kolalan "252/8-5 [22] Filed: Oct. 27, 1970 Primary Exanfiner-Herbert B. Guynn AttarneyThomas H. Whaley, Carl G. Reis and James F. 211 App]. No.: 84,514 Young 52 us. Cl. .l ..2s2/s.s c, 252/351 [571 ABSTRACT v [51] Int. Cl- UCIUIII 3/14 An aqueous drilling fluid dispersant and a, method of drilling [58] Field of Search ..252/8.5 C, 351; 260/625 wells using as the drilling fluid dispersant 4-allyldihydroxybenzene.

[56] References Cited UNITED STATES PATENTS 5 Claims, N0 Drawings 1,999,766 4/1935 Lawton etal ..252/8.5

DRILLING FLUID This invention relates to a novel aqueous drilling fluid for drilling wells through subsurface formations by means of well viscosity reducing agents for aqueous drilling fluids.

The 4-allyl-l,2-dihydroxybenzene of the present invention may be added to an aqueous drilling fluid in an amount rang- ,ing from about 0.1 pound to about 10 pounds per barrel of drilling panicflarly 9 an aqueous drilling drilling fluid. In general, it has been found that amounts less fluid havmg' Improved dlspembllityas a result of containing than 0.1 pound per barrel do not produce completely satisfactherein a novel dispersant as hereinafter more fully described. wry results in terms f dispersing activity whereas amounts The invention is also concerned with a method of drilling wells above about 0 bounds per band are economically memploying the nvel aqueous drilling fluid- 'tive and 'no improved results are obtained therewith. A

Drilling fluids, muds as y are Sometimes called, are 10 preferred range is from about 0.25.to about 7 pounds per barslul'l'ies of y y Solids used in the drilling of Wells for pp rel of drilling fluid for most consistent results and efficiency. underground collections of oil, gas brine or water. Such fluids Yield p i Yp is calculated by subtracting the pl fi f a number fhfferem functions, l most Important of Viscosity (PV) from the Fann Viscosity reading at 300 r.p.m. much are to ass! m the removal of cuttmgsfl'om the well to Plastic Viscosity (PV) is obtained by calculation, subtracting Seal off formations of oil or water which may be encmm' the Fann reading at 300 r.p.m. from the 600 r.p.m. reading. tered at different levels, to lubricate the drilling tool and drill Apparent viscosity (AV) is equal to enemaof the Fann R p which carries the hold the cuttings in p Viscosity reading obtained at 600 r.p.m. The fluidity of a mud event ofshmdowns m dnumgcan be back calculated from these data, the results bein ex- An ideal drilling fluid is a thixotropic colloidal system, i.e., a pressed in Fann Viscosity at 600 r.p.m. and 300 r.p.m. or a fluid which on agitation or circulation (as by pumping or direct reading viscosimeter. otherwise), has a measurable relatively low viscosity and is The properties of the base muds are shown in the table. free flowing (not plastic), particularly at high temperatures; The test data set forth in the following table indicate the adbut when such agitation or circulation is halted, the fluid sets vantages of 4-allyl-1,2-dihydroxybenzene in improving the or gels. The rate of gel formation is such as to permit the .dispersibility of drilling fluids. Y cuttings to fall only a short distance before the gel structure is Representative physical properties ofdrilling both be- TABLE Amount (ll)S./l)l)l.) Ar. and typo v :4. Ex. Additional additive, lbs. 'lype mud dispersant N Y! up. pll

Basemud.... ii :72 4h 1 r.pn .4 W2, 3: g: ,3 2...... Caustic to attain pH 9.6-0.8... Lpll l LpH=Lnw pH field-mud. 1 (A) =4-allyl-1,2 dlhydroxybenzene.

sufficiently strong to support them.

When such a drilling fluid having the proper viscosity, the proper gel rate and proper gel strength is circulated through a well bore, it has a sufficiently high viscosity to carry the v cuttings and sand from the bottom of the hole to the surface 1 and it has gel rate such as to allow the cuttings and sand to settle in a settling pit. On standing in a quiescent state, it develops sufficient gel strength to prevent the settling of the cuttings, sand or weighting material, etc., in the well bore when it becomes necessary to discontinue circulation for any appreciable period of time. Such a fluid is also characterized by its ability to form a mud cake on the borehole wall, thereby assisting in sealing off the traversed formations and inhibiting so-culled water loss, i.e., loss of water from the drilling fluid.

One of the principal problems in mud chemistry is the production of suitable drilling fluids having satisfactory dispersibility, and the necessary thixotropic properties discussed above.

In accordance with the present invention the problems of dispersibility in aqueous drilling fluids can be solved by incorporating in an aqueous drilling fluid as the dispersant 4-allyl- 1,2-dihydroxybenzene.

It is known from the article appearing in Zhur. Priklad.

Khem. 35, pages 638-647 (1962), Organic Viscosity Redu cers in Clay Solutions by D. Tischenko and S. Fleisher (CA, 57, 249lg, 1962), that the orthodihydroxybenzenesulfonic acids, the orthodihydroxyalphatoluenesulfonic acids and water soluble salts thereof are viscosity reducing agents in clay laden drilling fluids whereas the corresponding metaand para-dihydroxybenzenes including the corresponding sulfonic acid ri v WE?! s b s salts thsrs fiarqins fs t fore and after addition of the 4-allyl-l,Z-dihydroxybenzene are shown in the table. In each example the amount of materia] or materials added to the base mud, if any, is shown, expressed in terms of pounds of material per barrel of drilling ifluid.

I The table above shows that 4-allyl-l ,Z-dihydroxybenzene is ;an effective dispersant in low pH drilling fluids at concentrations of from 0.5 to 1.0 pound per barrel.

We claim:

1. An aqueous drilling fluid containing clay solids and as the dispersant at least 0.1 pound per barrel of drilling fluid of 4- 'allyll ,Z-dihydroxybenzene.

2. An aqueous drilling fluid as claimed in claim I wherein 4- allyl-l,Z-dihydroxybenzene is present in the drilling fluid in an amount of from about 0.1 to about 10 pounds per barrel of drilling fluid.

3. An aqueous drilling fluid as claimed in claim 1 wherein 4- allyl-l ,Z-dihydroxybenzene is present in the drilling fluid in an Iamount of from about 0.25 to about 7 pounds per barrel of drilling fluid.

4; In a method of drilling wells wherein a drilling fluid is ,passed through the well in contact with earth formations during the drilling operation, the improvement which comprises contacting said earth formations with an aqueous drilling fluid containing clay solids and as the dispersant at least 0.1 pound per barrel of drilling fluid of 4-allyl-l ,2-dihydroxybenzene.

5. A method as claimed in claim 4 wherein 4-allyl-l,2-

dihydroxybenzene is present in the drilling fluid in an amount of from about 0.25 to about 7 pounds per barrel of drilling fluidv 

2. An aqueous drilling fluid as claimed in claim 1 wherein 4-allyl-1,2-dihydroxybenzene is present in the drilling fluid in an amount of from about 0.1 to about 10 pounds per barrel of drilling fluid.
 3. An aqueous drilling fluid as claimed in claim 1 wherein 4-allyl-1,2-dihydroxybenzene is present in the drilling fluid in an amount of from about 0.25 to about 7 pounds per barrel of drilling fluid.
 4. In a method of drilling wells wherein a drilling fluid is passed through the well in contact with earth formations during the drilling operation, the improvement which comprises contacting said earth formations with an aqueous drilling fluid containing clay solids and as the dispersant at least 0.1 pound per barrel of drilling fluid of 4-allyl-1,2-dihydroxybenzene.
 5. A method as claimed in claim 4 wherein 4-allyl-1,2-dihydroxybenzene is present in the drilling fluid in an amount of from about 0.25 to about 7 pounds per barrel of drilling fluid. 